In many kinds of motors, the brushless direct current motor is usually used to achieve the heat-dissipating and air-discharging functions.
Generally, there is a motor for air-discharging in the toilet. The major goal of placing this kind of motor is to remove the odor inside the toilet to keep the freshness of the bathroom. However, due to the fact that this kind of motor is placed in the bathroom or in the toilet, it is easy to get wet all the time. Thus, the moisture-proof design for this kind of motor is an unavoidable issue.
The major goal of the moisture-proof design is to separate the stator part of the motor, which includes the circuit board, the core, and the coil, from its environment to achieve the moisture-proof purpose. Traditionally, the design is to coat a layer of the waterproof gum over the circuit board, the core, and the coil of the stator. However, it is costly.
FIG. 1 is the exploded diagram of the fan according to the prior art. As shown in FIG. 1, the blade 21 of the impeller is mounted on the portion of a rotor, and the stator, which includes the core 23, the printed circuit board 25, and the coil 26, is placed on the base 24. The fan is usually used for air-discharging purpose. Because it is used in the bathroom or the toilet, the lifetime of the coil 26, the circuit board 25, and the core 23 of the stator will decrease due to the moisture influence, Thus, it is necessary to overcome the above-described disadvantage.
FIG. 2 is an improvement over the device of FIG. 1. Basically, the stator is covered with a layer of insulating gum 27 for preventing from moisture. However, besides the coating step, the process has an additional baking step for drying the gum. It is significant that the gum has a certain thickness, so the baking step will spend a lot of time. Therefore, it will decrease the production efficiency.
It is therefore tried by the applicant to deal with the above situation encountered in the prior art.